The invention is directed to non-dusting, pourable granulate form preparations made from organosilanes liquid at room temperature and specific types of carbon black. The silane preparations are characterized particularly by surprisingly good storage stability, by resistance to hydrolysis of the silane component and by easy workability into rubber mixtures. A series of organosilicon compounds as is known is recommended and used in rubber technology. Especially known are sulfur containing alkoxysilanes which are predominantly suited as adhesive agents and reinforcers for vulcanizates of silica filler containing rubber mixtures. Particular mention is made of the organosilanes of Meyer-Simon U.S. Pat. No. 3,842,111. The entire disclosure of Meyer-Simon is hereby incorporated by reference and relied upon.
There are also known reinforcing additives for the mentioned rubber vulcanizates which are produced from the liquid organosilanes of Meyer-Simon U.S. Pat. No. 3,842,111 and silicate fillers (see German Pat. No. 2,255,577 and related Thurn U.S. Pat. No. 3,997,356. The entire disclosure of the Thurn U.S. patent is hereby incorporated by reference and relied upon).
All organosilanes which have previously found entrance in the art for the above mentioned uses are hydrolyzable liquids which upon contact with gaseous or liquid water condense to high molecular weight polysiloxanes with splitting out of alcohol and thereby can at least partially lose their effectiveness as reinforcing additives.
In the rubber working industry all chemical assistants which are liquid at room temperature, thus even the liquid organosilane, have severe disadvantages in comparison to solid chemical assistants, thus the increased difficulty of storing in silos, the increased difficulty in weighing and, above all in the production of mixtures on roller mixer mills, poor mixability.
The conversion of the liquid organosilane into powdery products, for example by mixing with precipitated silica, to be sure carries a certain advantage, but produces no optimum solution because even powdery products are relatively difficult to bring into rubber mixtures, long mixing times are required, dusting occurs and a disturbance and contamination of the environment and the machinery takes place. Furthermore, it has been estabilshed that the deposition of the organosilane occurring on the silicate containing filler particles does not eliminate the sensitivity to hydrolysis of the silane and that there occurs a definite loss in effectiveness in storage of the product. This is expressed for example in a lowering of the final value of cross-linking in rubber vulcanization.